Shoulder prosthesis

ABSTRACT

A prosthesis is provided and includes a central body having an outer surface and a longitudinal axis extending between a first end having an opening operable to receive an installation tool and a second end spaced apart from the first end. The outer surface extends between and connects the first end and the second end and defines the length of the central body. The prosthesis additionally includes a plurality of arms each attached to the outer surface of the central body and having an outer shape defined by a porous coating independent from a shape of the central body. The porous coating completely covers the outer surface of the central body between the first end and the second end.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/041,084 filed on Sep. 30, 2013, which is a continuation of U.S.patent application Ser. No. 13/343,039 filed on Jan. 4, 2012, which is acontinuation-in-part of U.S. patent application Ser. No. 13/182,026filed on Jul. 13, 2011 (now U.S. Pat. No. 8,506,638). The entiredisclosures of the above applications are incorporated herein byreference.

FIELD

The present disclosure relates to a shoulder prosthesis and moreparticularly to a shoulder prosthesis having a stemless humeralcomponent.

BACKGROUND

This section provides background information related to the presentdisclosure which is not necessarily prior art.

The shoulder joint includes the humerus, the clavicle, and the scapula,which cooperate to afford a range of motion of the humerus relative tothe scapula and clavicle during arm movement. Specifically, a proximalend of the humerus is disposed adjacent to the glenoid fossa of thescapula and is permitted to move relative to the glenoid fossa toprovide a range of motion to the humerus relative to the scapula.

Joint replacement surgery such as a partial or total shoulderarthroplasty may be required when the shoulder joint causes pain duringuse or is otherwise damaged. For example, the shoulder joint may bedamaged due to osteoarthritis, whereby progressive wearing away ofcartilage results in bare bone being exposed within the shoulder joint.Under such circumstances, it is often necessary to undergo a partial ortotal shoulder arthroplasty in order to relieve pain and increase therange of motion of the humerus by rebuilding portions of the shoulderjoint.

In performing a total shoulder arthroplasty, a surgeon resects a portionof the proximal end of the humerus that is received by the glenoidfossa. Once the distal end of the humerus is resected, the surgeon maythen ream the humerus to access the humeral canal. Providing access tothe humeral canal allows the surgeon to insert a humeral component intothe humeral canal. A prosthetic hemispherical humeral head may then beattached to a proximal end of the humeral component such that theresected portion of the humerus is replaced by the prosthetichemispherical humeral head. If necessary, the surgeon will likewisereplace a portion of the glenoid fossa to provide a bearing surfaceagainst which the humeral head may articulate. Upon completion of theshoulder arthroplasty, pain is typically alleviated and the patient isprovided with an increased range of motion at the shoulder joint.

While conventional shoulder prosthetics used during shoulderarthroplasty adequately provide the patient with an increased range ofmotion, conventional shoulder prosthetics require insertion of a steminto the humeral canal of the humerus, thereby increasing the overallweight, size, and cost of the humeral component. Furthermore, becausethe surgeon is required to insert the stem of the humeral component intothe humeral canal, the surgical procedure is somewhat complex, as thesurgeon is first required to resect the proximal end of the humerus andsubsequently ream the humeral canal prior to inserting the stem of thehumeral component into the humeral canal. Increasing the complexity ofthe joint-replacement surgery increases the time in which the surgeonmust spend in performing the procedure and therefore increases theoverall cost of the procedure. Finally, requiring insertion of the steminto the humeral component results in additional bone removal, therebyincreasing trauma and post-operative pain.

SUMMARY

This section provides a general summary of the disclosure, and is not acomprehensive disclosure of its full scope or all of its features.

In one configuration, a prosthesis is provided and includes a centralbody having an outer surface and a longitudinal axis extending between afirst end having an opening operable to receive an installation tool anda second end spaced apart from the first end. The outer surface extendsbetween and connects the first end and the second end and defines thelength of the central body. The prosthesis additionally includes aplurality of arms each attached to the outer surface of the central bodyand having an outer shape defined by a porous coating independent from ashape of the central body. The porous coating completely covers theouter surface of the central body between the first end and the secondend.

In another configuration, a prosthesis is provided and includes acentral body having a plurality of projections extending therefrom and aplurality of arms. The plurality of arms are respectively attached tothe central body via the plurality of projections and have an outershape defined by a porous coating. The porous coating extends throughthe plurality of projections.

Further areas of applicability will become apparent from the descriptionprovided herein. The description and specific examples in this summaryare intended for purposes of illustration only and are not intended tolimit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only ofselected embodiments and not all possible implementations, and are notintended to limit the scope of the present disclosure.

FIG. 1 is a side view of a humeral component of a shoulder prosthesis inaccordance with the principles of the present disclosure;

FIG. 2 is a top view of the humeral component of FIG. 1;

FIG. 3 is a perspective view of the humeral component of FIG. 1;

FIG. 4 is a side view of a humeral component of a shoulder prosthesis inaccordance with the principles of the present disclosure;

FIG. 5 is a top view of the humeral component of FIG. 4;

FIG. 6 is a perspective view of the humeral component of FIG. 4;

FIG. 7 is a side view of a humeral component of a shoulder prosthesis inaccordance with the principles of the present disclosure;

FIG. 8 is a top view of the humeral component of FIG. 7;

FIG. 9 is a perspective view of the humeral component of FIG. 7;

FIG. 10 is a cross-sectional view of the humeral component of FIG. 7taken along line 10-10 of FIG. 8;

FIG. 11 is a side view of a humeral component of a shoulder prosthesisin accordance with the principles of the present disclosure;

FIG. 12 is a top view of the humeral component of FIG. 11;

FIG. 13 is a perspective view of the humeral component of FIG. 11;

FIG. 14 is a side view of a humeral component of a shoulder prosthesisin accordance with the principles of the present disclosure;

FIG. 15 is a top view of the humeral component of FIG. 14;

FIG. 16 is a perspective view of the humeral component of FIG. 14;

FIG. 17 is a cross-sectional view of the humeral component of FIG. 14taken along line 17-17 of FIG. 15;

FIG. 18 is a cross-sectional view of the shoulder prosthesis of FIG. 14taken along line 17-17 of FIG. 15 and including an alternate armconstruction;

FIG. 19 is a cross-sectional view of the humeral component of FIG. 14taken along line 17-17 of FIG. 15 and including an alternate armconstruction;

FIG. 20 is a cross-sectional view of the humeral component of FIG. 14taken along line 17-17 of FIG. 15 and including an alternate armconstruction;

FIG. 21 is a cross-sectional view of the humeral component of FIG. 14taken along line 17-17 of FIG. 15 and including an alternate armconstruction;

FIG. 22 is a cross-sectional view of the humeral component of FIG. 14taken along line 17-17 of FIG. 15 and including an alternate armconstruction;

FIG. 23 is a perspective view of a humeral component of a shoulderprosthesis in accordance with the principles of the present disclosure;

FIG. 24 is a side view of the humeral component of FIG. 23;

FIG. 25 is a cross-sectional view of the humeral component of FIG. 24taken along line 25-25;

FIG. 26 is a partial cross-sectional view of the humeral component ofFIG. 24 taken along line 26-26;

FIG. 27 is a perspective view of a humeral component of a shoulderprosthesis in accordance with the principles of the present disclosure;

FIG. 28 is a side view of the humeral component of FIG. 27;

FIG. 29 is a partial cross-sectional view of the humeral component ofFIG. 28 taken along line 29-29;

FIG. 30 is a cross-sectional view of the humeral component of FIG. 28taken along line 30-30;

FIG. 31 is a perspective view of a humeral component of a shoulderprosthesis in accordance with the principles of the present disclosurereceiving a humeral head;

FIG. 32 is an exploded view of the humeral component and humeral head ofFIG. 31;

FIG. 33 is a partial perspective view of a proximal end of the humerusshowing a line of resection;

FIG. 34 is a partial side view of the humerus with a portion of the boneremoved to show a humeral component of a shoulder prosthesis inaccordance with the principles of the present disclosure received withina resected portion of the humerus; and

FIG. 35 is a partial side view of the humerus with a portion of the boneremoved to show a humeral component of a shoulder prosthesis inaccordance with the principles of the present disclosure being insertedtherein.

Corresponding reference numerals indicate corresponding parts throughoutthe several views of the drawings.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference tothe accompanying drawings.

Example embodiments are provided so that this disclosure will bethorough, and will fully convey the scope to those who are skilled inthe art. Numerous specific details are set forth such as examples ofspecific components, devices, and methods, to provide a thoroughunderstanding of embodiments of the present disclosure. It will beapparent to those skilled in the art that specific details need not beemployed, that example embodiments may be embodied in many differentforms and that neither should be construed to limit the scope of thedisclosure. In some example embodiments, well-known processes,well-known device structures, and well- known technologies are notdescribed in detail.

The terminology used herein is for the purpose of describing particularexample embodiments only and is not intended to be limiting. As usedherein, the singular forms “a,” “an,” and “the” may be intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. The terms “comprises,” “comprising,” “including,” and“having,” are inclusive and therefore specify the presence of statedfeatures, integers, steps, operations, elements, and/or components, butdo not preclude the presence or addition of one or more other features,integers, steps, operations, elements, components, and/or groupsthereof. The method steps, processes, and operations described hereinare not to be construed as necessarily requiring their performance inthe particular order discussed or illustrated, unless specificallyidentified as an order of performance. It is also to be understood thatadditional or alternative steps may be employed.

When an element or layer is referred to as being “on,” “engaged to,”“connected to,” or “coupled to” another element or layer, it may bedirectly on, engaged, connected or coupled to the other element orlayer, or intervening elements or layers may be present. In contrast,when an element is referred to as being “directly on,” “directly engagedto,” “directly connected to,” or “directly coupled to” another elementor layer, there may be no intervening elements or layers present. Otherwords used to describe the relationship between elements should beinterpreted in a like fashion (e.g., “between” versus “directlybetween,” “adjacent” versus “directly adjacent,” etc.). As used herein,the term “and/or” includes any and all combinations of one or more ofthe associated listed items.

Although the terms first, second, third, etc. may be used herein todescribe various elements, components, regions, layers and/or sections,these elements, components, regions, layers and/or sections should notbe limited by these terms. These terms may be only used to distinguishone element, component, region, layer or section from another region,layer or section. Terms such as “first,” “second,” and other numericalterms when used herein do not imply a sequence or order unless clearlyindicated by the context. Thus, a first element, component, region,layer or section discussed below could be termed a second element,component, region, layer or section without departing from the teachingsof the example embodiments.

Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,”“lower,” “above,” “upper,” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. Spatiallyrelative terms may be intended to encompass different orientations ofthe device in use or operation in addition to the orientation depictedin the figures. For example, if the device in the figures is turnedover, elements described as “below” or “beneath” other elements orfeatures would then be oriented “above” the other elements or features.Thus, the example term “below” can encompass both an orientation ofabove and below. The device may be otherwise oriented (rotated 90degrees or at other orientations) and the spatially relative descriptorsused herein interpreted accordingly.

With particular reference to FIGS. 1-3, a prosthesis 10 is provided andmay include a central body 12 and a plurality of wings or arms 14extending generally from the central body 12. The prosthesis 10 may bereceived within a resected humeral head (FIGS. 34, 35) and may providethe resected humerus with a structure to support a prosthetic humeralhead 16 (FIGS. 31, 34). The prosthetic humeral head 16 may be receivedby the prosthesis 10 once the prosthesis 10 is installed in the resectedhumerus during a partial or total shoulder arthroplasty or,alternatively, may be received by the prosthesis 10 prior to insertionof the prosthesis 10 into the proximal humerus.

The central body 12 may include a substantially cylindrical shape havinga longitudinal axis 18 and a bore 20 at least partially formed therein.The bore 20 may be substantially circular and may include a central axisthat is aligned with the longitudinal axis 18 and may include a firstportion 22 and a second portion 24. The first portion 22 is disposedproximate to an opening 26 of the central body 12 and may include aMorse taper. The second portion 24 is disposed generally adjacent to thefirst portion 22 and may include a smaller diameter than the firstportion 22. The second portion 24 may include a series of threads 28(FIG. 2) for use during installation or removal of the prosthesis 10from the humerus. The bore 20 may extend completely through the centralbody 12 and along the longitudinal axis 18 or, alternatively, may be ablind bore. Regardless of the particular construction of the bore 20,the first portion 22 is in fluid communication with the second portion24 such that access to the second portion 24 is obtained via the firstportion 22 at the opening 26 of the central body 12.

The central body 12 may include a substantially uniform outer surface 30and a distal end 32 having a radiused, beveled, or chamfered outer edge34. The radiused or beveled outer edge 34 may be positioned at thedistal end 32 to facilitate insertion of the distal end 32 into aresected end of the humerus during installation (FIGS. 34, 35).

The arms 14 extend generally away from the central body 12 in adirection substantially perpendicular to the longitudinal axis 18. Thearms 14 may be positioned relative to the central body 12 such that animaginary line 36 bisecting the central body 12 in a directionsubstantially perpendicular to the longitudinal axis 18 of the centralbody 12 extends through a pair of the arms 14 (FIG. 2). In oneconfiguration, the plurality of arms 14 may include six arms such thatthree such lines 36 may intersect the longitudinal axis 18 whileconcurrently passing through respective pairs of the six arms 14.

Each arm 14 may be integrally formed with the central body 12 and mayinclude a first end 38 disposed at a junction of each arm 14 and thecentral body 12 and a second end 40 formed at an opposite end of eacharm 14 from the first end 38. The first end 38 may be tapered toincrease the overall width of each arm 14 at the junction of each arm 14and the central body 12. Increasing the width of each arm 14 at ajunction of the central body 12 and each arm 14 increases the strengthof the arms at the junction between the arms 14 and the central body 12,thereby increasing the overall strength of each arm 14 and theconnection of each arm 14 to the central body 12.

The second end 40 of each arm 14 may include a series of alternatingpeaks 42 and valleys 44, as shown in FIG. 1. The peaks 42 may betruncated such that each peak 42 terminates at a substantially planarsurface 46. The valleys 44 may be positioned such that each valley 44 isdefined by a first surface 48 that is substantially perpendicular to thelongitudinal axis 18 of the central body 12 and a second surface 50 thatis substantially parallel to the longitudinal axis 18 of the centralbody 12.

With particular reference to FIGS. 4-6, a prosthesis 10 a is shown toinclude a central body 12 a and a plurality of wings or arms 14 a. Inview of the substantial similarity in structure and function of thecomponents associated with the prosthesis 10 with respect to theprosthesis 10 a, like reference numerals are used hereinafter and in thedrawings to identify like components while like reference numeralscontaining letter extensions are used to identify those components thathave been modified.

The central body 12 a may include a bore 20 a extending at leastpartially therethrough and along a longitudinal axis 18 of the centralbody 12 a. The bore 20 a may include a first portion 22 and a secondportion 24 a. The bore 20 may extend completely through the central body12 a or, alternatively, may be a blind bore that extends only partiallythrough the central body 12 a. Regardless of the particular constructionof the bore 20 a, the first portion 22 is in fluid communication withthe second portion 24 a such that the second portion 24 a is accessedvia the first portion 22 and opening 26 of the central body 12 a.

The second portion 24 a is disposed generally adjacent to the firstportion 22 and may include a substantially square shape. The shape ofthe second portion 24 a may be designed to matingly receive a tool (FIG.35) during installation of the prosthesis 10 a to prevent relativerotational movement between the prosthesis 10 a and the tool at thesecond portion 24 a. While the second portion 24 a is shown as includinga substantially square shape, the second portion 24 a could includevirtually any shape that permits the second portion 24 a of the bore 20to matingly receive a tool therein.

The arms 14 a extend generally from the central body 12 in a directionsubstantially perpendicular to the longitudinal axis 18 of the centralbody 12 a. As with the prosthesis 10, the plurality of arms 14 a mayinclude six arms 14 a, whereby a line 36 bisecting the central body 12 aand passing through the longitudinal axis 18 likewise passes through apair of the arms 14 a. Because the plurality of arms 14 a are shown toinclude six arms, three such lines 36 could be constructed. Each arm 14a may include a first end 38 disposed at a junction of the central body12 a and each arm 14 a as well as a second end 40. Further, each arm 14may include a series of alternating peaks 42 and valleys 44 at thesecond end 40, as shown in FIGS. 4 and 6.

The arms 14 a may additionally include a recess 52 that extendsgenerally between the outer surface 30 and the second end 40 of each arm14 a. The recess 52 may be defined by a first planar surface 54 and asecond planar surface 56 that are each substantially perpendicular tothe longitudinal axis 18, are substantially parallel to one another, andextend in different planes. A substantially vertical surface 58 mayextend generally between and connect the first planar surface 54 and thesecond planar surface 56 and may be substantially parallel to thelongitudinal axis 18 of the central body 12 a. The recess 52 allows forbone to grow over the top of each arm 14 a and for placement of bonegraft to help facilitate bone growth, which may allow for enhancedstability.

With particular reference to FIGS. 7-10, a prosthesis 60 is provided andmay include a central body 62 and a plurality of wings or arms 64. Aswith the prosthetics 10, 10 a, the prosthesis 60 may be received withina resected portion of a humerus during a partial or total shoulderarthroplasty. The prosthesis 60 provides a structure for receiving andsupporting a prosthetic humeral head 16 once the prosthesis 60 isinstalled in the resected portion of the humerus.

The central body 62 may include a bore 66 having a first portion 68 anda second portion 70. The first portion 68 may include a Morse taper andmay extend generally between a first end 72 of the central body 62 andthe second portion 70. The second portion 70 may be disposed adjacent tothe first portion 68 and may extend generally between the first portion68 and a second end 74 of the central body 62. The second portion 70 mayinclude a substantially square shape, as shown in FIG. 8, to matinglyreceive a tool (not shown) during installation of the prosthesis 60 intoa resected portion of a humerus. Interaction between the tool and thesecond portion 70 restricts relative rotation between the prosthesis 60and the tool at the second portion 70 during installation of theprosthesis 60 into the humerus. While the second portion 70 is describedand shown as including a substantially square shape, the second portion70 could include any shape that permits mating engagement with a toolduring installation of the prosthesis 60 to restrict relative rotationbetween the prosthesis 60 and the tool. Further, while the secondportion 70 is described as matingly receiving the tool to restrictrelative rotation therebetween, some rotation between the second portion70 and the tool may be permitted.

The bore 66 may extend completely through the central body 62 along alongitudinal axis 76 of the central body 62. While the bore 66 isdescribed and shown as extending completely through the central body 62along the longitudinal axis 76, the bore 66 could alternatively be ablind bore that only partially extends through the central body 62.

The central body 62 may additionally include a substantially uniformouter surface 78 as well as a chamfer 80 that facilitates insertion ofthe central body 62 into a resected portion of a humerus duringinstallation of the prosthesis 60. The outer surface 78 of the centralbody 62 may provide the central body 62 with a substantially constant,cylindrical shape extending along a length of the central body 62, asshown in FIG. 9.

The arms 64 extend generally from the central body 62 in a directionsubstantially perpendicular to the longitudinal axis 76. The pluralityof arms 64 may include six arms 64, whereby an imaginary line 82bisecting the central body 62 passes through a pair of arms 64 (FIG. 8).Because the plurality of arms 64 is shown as including six arms 64,three such lines 82 could be constructed.

Each arm 64 may include a proximal end 84 and a distal end 86. Theproximal end 84 may be located at a junction of each arm 64 and thecentral body 62 and may provide each arm 64 with an increased width atthe junction. Providing each arm 64 with an area of increased width atthe junction of the central body 62 and each arm 64 strengthens theconnection of the arms 64 to the central body 62 by increasing thematerial located at the junction of the central body 62 and the arms 64.

The distal end 86 of each arm 64 may include a first surface 88, asecond surface 90, and a third surface 92. The first surface 88 may beformed at an acute angle (β) relative to the longitudinal axis 76 of thecentral body 62 (FIG. 10). The second surface 90 may extend from thecentral body 62 in a direction substantially perpendicular to thelongitudinal axis 76 and may be located proximate to the second end 74of the central body 62. The third surface 92 may extend generallybetween the first surface 88 and the second surface 90 and may include aseries of peaks 94 and valleys 96. An imaginary line connecting thepeaks 94 may be formed at an obtuse angle (Ω) relative to the firstsurface (88) and may be formed at an acute angle (Σ) relative to thelongitudinal axis (76).

The arms 64 may additionally include a recess 98 disposed generallybetween the distal end 86 of each arm 64 and the outer surface 78 of thecentral body 62. The recess 98 may be defined generally by a firstplanar surface 100, a second planar surface 102, and a surface 104. Thefirst planar surface 100 and the second planar surface 102 extendgenerally from the central body 62 in a direction substantiallyperpendicular to the longitudinal axis 76. The first planar surface 100and the second planar surface 102 may be substantially parallel to oneanother and may be located in different planes such that the firstplanar surface 100 is located closer to the first end 72 of the centralbody 62 and the second planar surface 102 is located closer to thesecond end 74 of the central body 62, as shown in FIG. 10. The surface104 extends between the first planar surface 100 and the second planarsurface 102 to connect the first planar surface 100 and the secondplanar surface 102. The surface 104 may be planar and may be connectedto surfaces 100 and 102 by radii. The first planar surface 100, secondplanar surface 102, and surface 104 cooperate with the outer surface 78of the central body 62 to define the recess 98 of each arm 64.

With particular reference to FIGS. 11-13, a prosthesis 106 is shown toinclude a central body 108 and a plurality of wings or arms 110. As withthe prosthetics 10, 10 a, 60, the prosthesis 106 may be used during apartial or total shoulder arthroplasty and may be received within aresected portion of a humerus. The prosthesis 106 may provide astructure on which a prosthetic humeral head 16 may be supportedrelative to the resected portion of the humerus.

The central body 108 may include a substantially circular shape and mayinclude a bore 112 at least partially formed therethrough and extendingalong a longitudinal axis 114 of the central body 108. The bore 112 mayinclude a first portion 116 and a second portion 118. The bore 112 mayextend completely through the central body 108 or, alternatively, thebore 112 may be a blind bore extending only partially through thecentral body 108. Regardless of the particular construction of the bore112, the first portion 116 may include a Morse taper for receiving aportion of the prosthetic humeral head 16.

The second portion 118 may include a series of threads (not shown) or,alternatively, a shape for mating engagement with a tool (FIG. 35). Thetool may matingly engage the second portion 118 to facilitate attachmentbetween the tool and the central body 108 of the prosthesis 106 duringinstallation of the prosthesis 106 into the resected portion of thehumerus during a partial or total shoulder arthroplasty. Engagementbetween the tool and the second portion 118 of the central body 108inhibits relative rotation between the tool and the central body 108during installation of the prosthesis 106 and, as a result, enhances theability of the tool to engage and position the prosthesis 106 within theresected portion of the humerus.

The central body 108 may additionally include an outer surface 120 thatdefines the substantially cylindrical shape of the central body 108. Theouter surface 120 may extend between a first end 122 and a second end124 (FIG. 11). The second end 124 may include a chamfer 126 tofacilitate insertion of the central body 108 into the resected portionof the humerus.

With continued reference to FIGS. 11-13, the arms 110 are shown asincluding a first end 128 and a second end 130. The first end 128 mayinclude an increased thickness at a junction of the central body 108 andeach arm 110 to increase the overall contact area between the centralbody 108 and each arm 110. Increasing the thickness of each arm 110 atthe first end 128 increases the strength of the arms 110 at the centralbody 108 and, as a result, improves the overall strength of theprosthesis 106.

The second end 130 is formed on an opposite end of each arm 110 from thefirst end 128 and may include a first planar surface 132, a secondplanar surface 134, and a third planar surface 136. The first planarsurface 132, second planar surface 134, and third planar surface 136 mayall be formed at an acute angle relative to the longitudinal axis 114 ofthe central body 108. For example, the first planar surface 132 may beformed at an acute angle (θ) relative to the longitudinal axis 114, thesecond planar surface 134 may be formed at an acute angle (ψ), and thethird planar surface 136 may be formed at an acute angle (φ) relative tothe longitudinal axis 114. In addition, the first planar surface 132,second planar surface 134, and third planar surface 136 may be formed atan obtuse angle relative to one another. For example, the third planarsurface 136 may be formed at an obtuse angle (δ) relative to the secondplanar surface 134. Likewise, the second planar surface 134 may beformed at an obtuse angle (σ) relative to the first planar surface 132.

The arms 110 may extend from the central body 108 in a directionsubstantially perpendicular to the longitudinal axis 114 of the centralbody 108. As such, an imaginary line 138 passing through thelongitudinal axis 114 and bisecting the central body 108 likewise passesthrough a pair of the arms 110, as shown in FIG. 12. Because theplurality of arms 110 is shown to include six arms, three such lines 138could be constructed.

The arms 110 may include a recess 140 extending generally between theouter surface 120 of the central body 108 and the second end 130 of eacharm 110. The recess 140 may be defined generally by a first planarsurface 142, a second planar surface 144, and a third planar surface146. The first planar surface 142 and the second planar surface 144 mayextend generally from the central body 108 in a direction substantiallyperpendicular to the longitudinal axis 114. The first planar surface 142may be substantially parallel to the second planar surface 144, wherebythe first planar surface 142 and the second planar surface 144 extend indifferent planes.

As described, the first planar surface 142 is disposed closer to thefirst end 122 of the central body 108 and the second planar surface 144is disposed closer to the second end 124 of the central body 108. Thethird planar surface 146 is disposed generally between the first planarsurface 142 and the second planar surface 144 and may be formedsubstantially parallel to the longitudinal axis 114 of the central body108. As such, the third planar surface 146 may be substantially parallelto the outer surface 120 of the central body 108 to define the recesses140 of the arms 110.

With particular reference to FIGS. 23-26, a prosthesis 200 is shown toinclude a central body 202 and a plurality of wings or arms 204. As withthe prosthetics 10, 10 a, 60, 106, the prosthesis 200 may be used duringa partial, total, or reverse shoulder arthroplasty and may be receivedwithin a resected portion of a humerus. The prosthesis 200 may provide astructure on which a prosthetic humeral head 16 may be supportedrelative to the resected portion of the humerus.

The central body 202 may include a substantially circular shape and mayinclude a bore 206 at least partially formed therethrough and extendingalong a longitudinal axis 208 (FIG. 25) of the central body 202. Thebore 206 may include a first portion 210 and a second portion 212. Thebore 206 may extend completely through the central body 202 or,alternatively, the bore 206 may be a blind bore extending only partiallythrough the central body 202. Regardless of the particular constructionof the bore 206, the first portion 210 may include a Morse taper forreceiving a portion of a reverse humeral tray (not shown) or a portionof the prosthetic humeral head 16. Further, the first portion 210 mayinclude a substantially uniform inner surface (FIG. 25) or,alternatively, may include a series of threads or steps, as shown inconjunction with the device shown in FIG. 30.

The second portion 212 may include a series of threads 214 or,alternatively, a shape for mating engagement with a tool (FIG. 35). Thetool may matingly engage the second portion 212 to facilitate attachmentbetween the tool and the central body 202 of the prosthesis 200 duringinstallation of the prosthesis 200 into the resected portion of thehumerus during a partial or total shoulder arthroplasty. Engagementbetween the tool and the second portion 212 of the central body 202inhibits relative rotation between the tool and the central body 202during installation of the prosthesis 200 and, as a result, enhances theability of the tool to engage and position the prosthesis 200 within theresected portion of the humerus.

The central body 202 may additionally include an outer surface 216 thatdefines the substantially cylindrical shape of the central body 202. Theouter surface 216 may extend between a first end 218 and a second end220 (FIG. 24). The second end 220 may include a chamfer (not shown) tofacilitate insertion of the central body 202 into the resected portionof the humerus.

With continued reference to FIGS. 23-26, the arms 204 are shown asincluding a first end 222 and a second end 224. The first end 222 may beattached to the central body 202 such that the arms 204 extend from thecentral body 202 in a first direction (D1) substantially perpendicularto the longitudinal axis 208. The arms 204 may be located relative tothe central body 202 such that an imaginary line passing through thelongitudinal axis 208 and bisecting the central body 202 likewise passesthrough a pair of the arms 204. Because the plurality of arms 204 isshown to include six arms, three such lines could be constructed.

The second end 224 is formed on an opposite end of each arm 204 from thefirst end 222 and may include a greater width than the first end 222measured in a second direction (D2) substantially perpendicular to thefirst direction (D1). Providing the second end 224 with a greater widththan the first end 222 may also provide each arm 204 with a taperedsurface 226 extending generally between the first end 222 and the secondend 224. The tapered surface 226 may additionally include a series ofsteps 228 that cooperate to define a series of recesses 230.

The steps 228 and recesses 230 may be used to retain the prosthesis 200once installed by allowing cement, bone-growth material, and/or othermaterial to collect within each recess 230. Further, each recess 230 mayterminate at an edge 232 of an adjacent step 228, whereby the edge 232is positioned to engage the surrounding bone and/or tissue to restrictremoval of the prosthesis 200 once installed. The edge 232 may include asomewhat sharp corner that allows the edge 232 to facilitate engagementwith the surrounding bone.

During installation, the prosthesis 200 is driven into a resectedhumerus and applies a force on the surrounding bone due to the taperedsurfaces 226 of the arms 204. Specifically, the resected humerus istypically prepared such that the humerus includes a size and shape thataccommodates the prosthesis 200. For example, the resected humerus couldbe undersized relative to the prosthesis 200 such that the prosthesis200 is in a press-fit relationship with the humerus upon installation.Alternatively, the resected humerus could be oversized to allow theprosthesis 200 to be cemented within the humerus.

Assuming the resected humerus is undersized relative to the prosthesis200, when the prosthesis 200 is driven into the humerus, the taperedsurfaces 226 of the arms 204 apply a compressive force on thesurrounding bone, thereby ensuring a tight fit between the prosthesis200 and the bone. This tight fit may be maintained due to engagementbetween the edges 232 of the steps 228 and the surrounding bone when theprosthesis 200 is forcibly inserted into a resected humerus and mayretain a position of the prosthesis 200 relative to the humerus once theforce applied to the prosthesis 200 is released.

The arms 204 may also include a series of steps 234 and recesses 236formed in a surface 238 of the arms 204 that extends generally betweenthe first end 222 and the second end 224. As with the steps 228 andrecesses 230, the steps 234 and recesses 236 may facilitate retention ofthe prosthesis 200 within a humerus by allowing cement, bone-growthmaterial, and/or other material to collect within each recess 236.

The arms 204 may include a recess 240 extending generally between theouter surface 120 of the central body 202 and the second end 224 of eacharm 204. The recess 240 may receive cement, bone-growth material, and/orother material to help retain the prosthesis 200 within the resectedhumerus.

With particular reference to FIGS. 27-30, a prosthesis 300 is shown toinclude a central body 302 and a plurality of wings or arms 304. As withthe prosthetics 10, 10 a, 60, 200 the prosthesis 300 may be used duringa partial or total shoulder arthroplasty and may be received within aresected portion of a humerus. The prosthesis 300 may provide astructure on which a prosthetic humeral head 16 may be supportedrelative to the resected portion of the humerus.

The central body 302 may include a substantially circular shape and mayinclude a bore 306 at least partially formed therethrough and extendingalong a longitudinal axis 308 (FIG. 25) of the central body 302. Thebore 306 may include a first portion 310 and a second portion 312. Thebore 306 may extend completely through the central body 302 or,alternatively, the bore 306 may be a blind bore extending only partiallythrough the central body 302. Regardless of the particular constructionof the bore 306, the first portion 310 may include a Morse taper forreceiving a portion of the prosthetic humeral head 16. Further, thefirst portion 310 may include a substantially uniform inner surface (asis shown in FIG. 25 with respect to prosthesis 200) or, alternatively,may include a series of threads or steps 311 (FIG. 30).

The second portion 312 may include a series of threads 314 or,alternatively, a shape for mating engagement with a tool (FIG. 35). Thetool may matingly engage the second portion 312 to facilitate attachmentbetween the tool and the central body 302 of the prosthesis 300 duringinstallation of the prosthesis 300 into the resected portion of thehumerus during a partial or total shoulder arthroplasty. Engagementbetween the tool and the second portion 312 of the central body 302inhibits relative rotation between the tool and the central body 302during installation of the prosthesis 300 and, as a result, enhances theability of the tool to engage and position the prosthesis 300 within theresected portion of the humerus.

The central body 302 may additionally include an outer surface 316 thatdefines the substantially cylindrical shape of the central body 302. Theouter surface 316 may extend between a first end 318 and a second end320 (FIG. 28). The second end 320 may include a chamfer (not shown) tofacilitate insertion of the central body 302 into the resected portionof the humerus.

With continued reference to FIGS. 27-30, the arms 304 are shown asincluding a first end 322 and a second end 324. The first end 322 may beattached to the central body 302 such that the arms 304 extend from thecentral body 302 in a first direction (D1) substantially perpendicularto the longitudinal axis 308. The arms 304 may be located relative tothe central body 302 such that an imaginary line passing through thelongitudinal axis 308 and bisecting the central body 302 likewise passesthrough a pair of the arms 304. Because the plurality of arms 304 isshown to include six arms, three such lines could be constructed.

The second end 324 is formed on an opposite end of each arm 304 from thefirst end 322 and may include a greater width than the first end 22measured in a second direction (D2) substantially perpendicular to thefirst direction (D1). Providing the second end 324 with a greater widththan the first end 322 may also provide each arm 304 with a taperedsurface 326 extending generally between the first end 322 and the secondend 324. The tapered surface 326 may be substantially planar, therebyproviding each arm 304 with a substantially smooth surface extendingbetween the first end 322 and the second end 324.

During installation, the prosthesis 300 is driven into a resectedhumerus and may apply a force on the surrounding bone due to the taperedsurfaces 326 of the arms 304. Specifically, the resected humerus istypically prepared such that the humerus includes a size and shape thatis either undersized or oversized relative to the prosthesis 300.Namely, the resected humerus may be undersized to provide a press-fitbetween the resected humerus and the prosthesis 300 upon installationor, alternatively, could be oversized to allow the prosthesis 300 to becemented within the humerus. Assuming that the resected humerus isundersized, when the prosthesis 300 is driven into the humerus, thetapered surfaces 326 of the arms 304 apply a compressive force on thesurrounding bone, thereby ensuring a tight fit between the prosthesis300 and the bone.

The arms 304 may also include a series of steps 334 and recesses 336formed in a surface 338 of the arms 304 that extends generally betweenthe first end 322 and the second end 324. The steps 334 and recesses 336may facilitate retention of the prosthesis 300 within a humerus byallowing cement, bone-growth material, and/or other material to collectwithin each recess 336.

The arms 304 may include a recess 340 extending generally between theouter surface 120 of the central body 302 and the second end 324 of eacharm 304. The recess 340 may receive cement, bone-growth material, and/orother material to help retain the prosthesis 300 within the resectedhumerus.

While the prosthetics 200, 300 are described as including taperedsurfaces, any of the prosthetics 10, 10 a, 60, 106 could similarlyinclude tapered surfaces to facilitate retention of the prosthetics 10,10 a, 60, 106 in the resected humerus. Namely, each of the prosthetics10, 10 a, 60, 106, 200, 300 could include arms having tapered surfacesin a similar fashion as shown and described with respect to taperedsurfaces 226, 326 of prosthetics 200, 300.

The foregoing prosthetics 10, 10 a, 60, 106, 200, 300 may be formed fromany suitable biocompatible material. For example, the prosthetics 10, 10a, 60, 106, 200, 300 may be formed from a titanium alloy (e.g.,Ti-6AI-4V), CoCrMo, Pyrocarbon, or PEEK. In addition, the central bodies12, 12 a, 62, 108, 202, 302 and/or arms 14, 14 a, 64, 110, 204, 304 maybe coated with a porous plasma spray (PPS), Regenerex, or HydroxyApatite (HA), or any other appropriate coating that promotes boneyingrowth or ongrowth. Providing the various prosthetics 10, 10 a, 60,106, 200, 300 with such a coating to promote boney ingrowth or ongrowthhelps ensure that the prosthesis 10, 10 a, 60, 106, 200, 300 is retainedat a desired position within the resected humerus by encouraging boneyingrowth and/or ongrowth that helps retain the prosthetics 10, 10 a, 60,106, 200, 300 at the desired position relative to the humerus.

The prosthetics 10, 10 a, 60, 106, 200, 300 may be formed from atraditional manufacturing method such as, for example, machining orforging. Alternatively, the prosthetics 10, 10 a, 60, 106, 200, 300 maybe formed from an additive manufacturing process such as Electron BeamMelting (EBM) or Direct Metal Laser Sintering (DMLS). If the prosthetics10, 10 a, 60, 106, 200, 300 are formed from an additive manufacturingprocess, the prosthetics 10, 10 a, 60, 106, 200, 300 may be machinedthereafter to form the Morse taper and inserter mating features withinthe bores 20, 20 a, 66, 112, 206, 306 of the respective prosthetics 10,10 a, 60, 106, 200, 300.

Utilizing an additive manufacturing process allows the prosthetics 10,10 a, 60, 106, 200, 300 to be formed in a substantially net shape andmay provide each prosthesis 10, 10 a, 60, 106, 200, 300 with asubstantially mesh or porous structure. Furthermore, manufacturing theprosthetics 10, 10 a, 60, 106, 200, 300 via an additive manufacturingprocess allows the prosthetics 10, 10 a, 60, 106, 200, 300 to includeareas of solid material adjacent to or embedded within the porousstructure of the prosthesis 10, 10 a, 60, 106, 200, 300.

With particular reference to FIGS. 14-22, various configurations of theprosthesis 106 are provided, whereby the prosthesis 106 is formed via anadditive manufacturing process. FIGS. 14-21 depict at least a portion ofthe central body 108 and arms 110 as being formed from a porousmaterial, whereby the central body 108 and/or arms 110 include poresformed in between biomaterial. While the prosthesis 106 is described andshown as being formed from an additive manufacturing process and asincluding a mesh or porous material at the central body 108 and/or arms110, any of the prosthetics 10, 10 a, 60, 200, 300 could be formed viaan additive manufacturing process to include a mesh or porous material.

FIGS. 14-16 generally depict the prosthesis 106 as including a porousmaterial that forms a portion of the central body 108 and at least aportion of the arms 110. For example, the cross-sectional view of FIG.17 identifies a portion of the central body 108 and arms 110 as beingformed from a porous material. Forming a portion of the central body 108from a porous material allows the central body 108 to be machined. Forexample, the central portion 108 may be machined to include a taper toallow the central portion 108 to properly receive an installation tooland subsequently a portion of a humeral head 16.

The arms 110 are shown as including a solid portion 148 disposedgenerally within the arms 110 and connected to the central portion 108.The solid portion 148 may be configured such that the solid portion 148mimics the outer profile of each arm 110, whereby the solid portion 148similarly includes a first surface 150, a second surface 152, and athird surface 154. Namely, the first surface 150, second surface 152,and third surface 154 are respectively disposed adjacent and parallel tosurfaces 132, 134, and 136 of each arm 110. In addition, the solidportion 148 may include a fourth surface 156 that is substantiallyparallel to the first planar surface 142 and a fifth surface 158 that issubstantially parallel to the outer surface 120 of the central body 108.

The solid portion 148 may be surrounded by a porous material and may bepositioned within the arms 110 at virtually any location and may includevirtually any shape to provide each arm 110 with additional strength.During manufacturing of the prosthesis 106, the porous material, as wellas the solid portion 148, may be formed by depositing layer upon layeruntil the shape of the prosthesis 106 shown in FIG. 17 is obtained. Forexample, the layers may be added to one another in any of the (W), (X),(Y), and (Z) directions during manufacturing (FIG. 17).

With particular reference to FIG. 18, the prosthesis 106 is shown toinclude a solid portion 160 having a similar shape to that of the solidportion 148. While the solid portion 160 includes a substantiallysimilar shape as the solid portion 148, the solid portion 160 of FIG. 18includes additional solid material when compared to the solid portion148 of FIG. 17. Providing the prosthesis 106 with additional solidmaterial, as shown in FIG. 18, additionally strengthens the arms 110and, thus, strengthens the overall prosthesis 106.

With particular reference to FIG. 19, the prosthesis 106 is shown asbeing formed entirely from a porous material, except for a portion ofthe central body 108 to allow the central portion 108 to be machined. Inthis configuration, the central body 108 and arms 110 are completelyformed from a porous material and do not include a solid portion, asshown in FIGS. 17 and 18.

With particular reference to FIG. 20, the prosthesis 106 is shown asincluding a solid portion 162 having a different configuration than thesolid portions 148, 160 of FIGS. 17 and 18, respectively. The solidportion 162 includes a first surface 164 that is substantially parallelto the third planar surface 136, as well as a pair of planar surfaces166 that are substantially parallel to the longitudinal axis 114 of thecentral body 108. Additionally, the solid portion 162 may include a pairof planar surfaces 168 that are substantially perpendicular to thelongitudinal axis 114 of the central body 108.

With particular reference to FIG. 21, the prosthesis 106 is shown asincluding a solid portion 170 having a pair of planar surfaces 172 thatare substantially parallel to the longitudinal axis 114 of the centralbody 108 and a pair of planar surfaces 174 that are substantiallyperpendicular to the longitudinal axis 114 of the central body 108. Aswith the solid portions 148, 160, 162, the solid portion 170 adds to theoverall strength of the prosthesis 106 by extending into the arms 110 inan effort to strengthen the arms 110 proximate to a junction of thecentral body 108 and the arms 110.

With particular reference to FIG. 22, the prosthesis is shown withouthaving any regions of porous material. As such, the prosthesis 106 shownin FIG. 22 is entirely solid and therefore may be coated with a coating176 that promotes boney ingrowth or ongrowth once installed in thehumerus.

With particular reference to FIGS. 31-35, installation of the prosthesis10 will be described in detail. While the following installation will bedescribed with respect to the prosthesis 10, the following installationcould be performed with any of the prosthetics 10, 10 a, 60, 106, 200,300.

During a partial or total shoulder arthroplasty, a surgeon first makesan incision proximate to the shoulder joint of the patient to expose thehumerus and glenoid fossa. Once exposed, the surgeon may use a template(not shown) to make a resection of the humerus 178 along line 180 ofFIG. 33. Once the humerus 178 is resected, the surgeon may then use atool such as a central pin and reamer/broach (none shown) to prepare aproximal end of the humerus 178 to allow the humerus 178 to receive theprosthesis 10. In one configuration, the reamer/broach creates a centralpocket for receiving the central body 12 as well as a series of recessesextending from the central body 12 in spaced relation to one another inan effort to matingly receive the arms 14 once the prosthesis 10 isinserted into the humerus 178.

Prior to inserting the prosthesis 10 into the humerus 178, a suitableadhesive and/or coating may be applied to both retain the prosthesis 10within the humerus 178 and to promote boney ingrowth and/or ongrowth. Ifthe prosthesis 10 includes a recess such as recesses 52 of prosthesis 10a, recess 98 of prosthesis 60, or recess 140 of prosthesis 106, a bonegraft material may additionally be applied therein to further retain theprosthesis 10 within the humerus 178 and to promote bone growth over andwithin the recesses 52, 98, 140.

Once the prosthesis 10 is positioned relative to the humerus 178, a toolmay be received within the bore 20 and may threadably engage the threads28 of the second portion 28 of the bore 20 (FIG. 35). A force may beapplied to the tool in the direction (Z) shown in FIG. 35 to drive theprosthesis 10 into the humerus 178 until the prosthesis 10 is positionedin a desired position relative to the humerus 178.

Once the prosthesis 10 is disposed within the humerus 178, a tool 182may be used to position the prosthetic humeral head 16 relative to theprosthesis 10 such that a portion of the prosthetic humeral head 16 isreceived within the bore 20 of the prosthesis 10. Specifically, theprosthetic humeral head 16 may include an extension 184 having a Morsetaper. The extension 184 may include a male Morse taper while the firstportion 22 of the bore 20 includes a mating female Morse taper such thatwhen the extension 184 is received within the bore 20 of the centralbody 12, the prosthetic humeral head 16 is retained by the prosthesis 10and held in a desired position relative to the humerus 178.

The foregoing description of the embodiments has been provided forpurposes of illustration and description. It is not intended to beexhaustive or to limit the disclosure. Individual elements or featuresof a particular embodiment are generally not limited to that particularembodiment, but, where applicable, are interchangeable and can be usedin a selected embodiment, even if not specifically shown or described.The same may also be varied in many ways. Such variations are not to beregarded as a departure from the disclosure, and all such modificationsare intended to be included within the scope of the disclosure.

What is claimed is:
 1. A prosthesis comprising: a central body having anouter surface and a longitudinal axis extending between a first endhaving an opening operable to receive an installation tool and a secondend spaced apart from said first end, said outer surface extendingbetween and connecting said first end and said second end and definingthe length of said central body; and a plurality of arms each attachedto said outer surface of said central body and having an outer shapedefined by a porous coating independent from a shape of said centralbody, said porous coating completely covering said outer surface of saidcentral body between said first end and said second end.
 2. Theprosthesis of claim 1, wherein said solid body includes projectionsextending from said outer surface and into respective ones of saidplurality of arms, said porous coating covering said projections anddefining said outer shape of said plurality of arms independent from ashape of said projections.
 3. The prosthesis of claim 2, wherein saidporous coating includes a different thickness at different locationsaround said projections.
 4. The prosthesis of claim 2, wherein saidplurality of arms each include a first surface, a second surface, and athird surface that are each formed at an obtuse angle relative to oneanother to define said outer shape of said plurality of arms.
 5. Theprosthesis of claim 4, wherein said projections each include a fourthsurface, a fifth surface, and a sixth surface that are each formed at anobtuse angle relative to one another and respectively oppose said firstsurface, said second surface, and said third surface of said pluralityof arms.
 6. The prosthesis of claim 4, wherein said projections eachinclude a fourth surface formed substantially perpendicular to saidlongitudinal axis and a fifth surface formed substantially perpendicularto said longitudinal axis, said fourth surface and said fifth surfaceextending from said outer surface at a first end.
 7. The prosthesis ofclaim 6, wherein said projections each include a sixth surface joiningsaid fourth surface and said fifth surface at a second end of each ofsaid projections that is formed on an opposite end of each of saidprojections than said first end, said sixth surface formed substantiallyparallel to said longitudinal axis.
 8. The prosthesis of claim 2,wherein said porous material extends through said projections.
 9. Theprosthesis of claim 1, wherein said central body is formed from a solidmaterial.
 10. The prosthesis of claim 9, wherein said solid materialextends into said plurality of arms.
 11. The prosthesis of claim 10,wherein said solid material disposed within said plurality of armsincludes a different shape than said outer shape of said plurality ofarms.
 12. The prosthesis of claim 9, wherein said solid material isspaced apart and separated from said plurality of arms.
 13. A prosthesiscomprising: a central body having a plurality of projections extendingtherefrom; and a plurality of arms respectively attached to said centralbody via said plurality of projections and having an outer shape definedby a porous coating, said porous coating extending through saidplurality of projections.
 14. The prosthesis of claim 13, wherein saidporous coating covers said projections and defines said outer shape ofsaid plurality of arms independent from a shape of said plurality ofprojections.
 15. The prosthesis of claim 13, wherein said porous coatingextends through said plurality of projections within said plurality ofarms.
 16. The prosthesis of claim 13, wherein said plurality of armseach include a first surface, a second surface, and a third surface thatare each formed at an obtuse angle relative to one another to definesaid outer shape of said plurality of arms.
 17. The prosthesis of claim16, wherein said plurality of projections each include a fourth surface,a fifth surface, and a sixth surface that are each formed at an obtuseangle relative to one another and respectively oppose said firstsurface, said second surface, and said third surface of said pluralityof arms.
 18. The prosthesis of claim 13, wherein said central body isformed from a solid material.
 19. The prosthesis of claim 18, whereinsaid plurality of projections are formed from said solid material. 20.The prosthesis of claim 19, wherein said plurality of projections eachinclude an aperture formed through said solid material within saidplurality of arms, said porous material extending through said pluralityof projections at said apertures.